Retaining

About Retaining

Retaining compounds, also known as bearing fit retainers or thread lockers, are specialised anaerobic adhesives designed to secure cylindrical assemblies and fill the microscopic gaps between mating metal surfaces. These high-performance chemical solutions provide a reliable alternative to traditional mechanical methods like pins, keys, and press fits, creating a strong, vibration-resistant bond that prevents loosening, leakage, and corrosion in mechanical assemblies.

The retaining compounds available at TooledUp.com are engineered for demanding workshop and industrial applications, from securing bearings and bushings to locking gears and pulleys onto shafts. Available in various strength grades, these anaerobic adhesives cure in the absence of air when confined between close-fitting metal surfaces, transforming from a liquid into a tough thermoset plastic that can withstand extreme temperatures, vibration, and chemical exposure. Whether you're working on automotive repairs, hydraulic systems, or general engineering projects, the right retaining compound eliminates the need for expensive machining tolerances whilst increasing the load-bearing capacity of assemblies.

Our selection includes both standard and specialised formulations, with options for oil-tolerant applications, high-strength permanent bonds, and bearing fit solutions. Leading brands like Bondloc and Sealey provide professional-grade compounds trusted by engineers and maintenance technicians across the UK, ensuring reliable performance in workshop environments and on-site repairs alike.

Jargon Buster

• Anaerobic Adhesive: A type of adhesive that cures in the absence of air when confined between close-fitting metal surfaces, remaining liquid when exposed to oxygen but hardening rapidly when trapped in the gap between components.
• Retaining Compound: A specialised adhesive designed specifically to secure cylindrical parts such as bearings, bushings, and cylindrical components onto shafts or into housings, filling microscopic gaps to create a solid, load-bearing assembly.
• Bearing Fit: The dimensional relationship between a bearing and its housing or shaft. Retaining compounds can compensate for worn or oversized fits, restoring assemblies to serviceable condition without expensive machining.
• Shear Strength: The maximum load a cured retaining compound can withstand before failure when force is applied parallel to the bonded surface, measured in megapascals (MPa) or pounds per square inch.
• Oil Tolerant: A formulation capable of curing on surfaces with light oil contamination, eliminating the need for perfect degreasing in maintenance and repair situations where complete cleaning isn't practical.
• Gap Fill: The maximum distance between mating surfaces that a retaining compound can effectively bridge whilst maintaining full strength, typically ranging from 0.10mm to 0.50mm depending on the product specification.

Who Uses Retaining?

Retaining compounds are essential for a wide range of trades and industries:

• Mechanical Engineers - for machinery assembly, refurbishment, and maintenance work
• Automotive Technicians - securing bearings, bushings, and transmission components
• Plant Maintenance Fitters - repairing worn assemblies on production equipment
• Hydraulic Engineers - sealing and securing hydraulic pump and motor components
• Agricultural Mechanics - repairing farm machinery with worn tolerances
• Marine Engineers - maintaining marine engines and propulsion systems
• General Engineering Workshops - for fabrication and repair projects
• Maintenance Contractors - conducting on-site repairs without specialist machining facilities
• Manufacturing Facilities - production line assembly and quality assurance applications

How to Choose the Right Retaining

Selecting the appropriate retaining compound depends on several critical factors:

Strength Requirements: High-strength formulations like Bondloc B638 create permanent bonds ideal for static assemblies, whilst medium-strength variants allow for disassembly with heating when future maintenance is anticipated. Consider whether the assembly needs to be serviceable or permanently secured.

Surface Condition: Standard retaining compounds require clean, degreased surfaces for optimal performance. If working with surfaces that have oil residue or can't be thoroughly cleaned, opt for oil-tolerant formulations specifically designed to cure despite light contamination.

Gap Size: Bearing fit retainers are formulated for larger clearances (up to 0.38mm), whilst general retaining compounds work best in gaps under 0.25mm. Measure your clearance carefully or choose a versatile bearing fit product for worn or oversized assemblies.

Temperature Exposure: Check the operating temperature range of your chosen compound. Most professional retaining compounds withstand continuous temperatures between -55°C and +150°C, but specific applications may require specialised high-temperature formulations.

Cure Time: Consider your production or repair schedule. Fixture times vary from 5 to 30 minutes, with full cure strength typically achieved within 24 hours at room temperature. Some applications may benefit from heat-accelerated curing.

Certifications: For critical applications in regulated industries, verify that your chosen product meets relevant standards and has appropriate approvals for your sector, whether automotive, food processing, or other specialised environments.

Popular Accessories

• Activators and Primers: Surface treatments that accelerate cure speed on inactive surfaces or in cold conditions
• Degreasing Solvents: Specialist cleaners for preparing metal surfaces before adhesive application
• Dispensing Equipment: Precision applicator bottles and needles for controlled compound placement
• Thread Lockers: Complementary anaerobic adhesives for securing threaded fasteners
• Gasket Makers: Related sealing compounds for flanges and mating surfaces
• Surface Wipes: Pre-saturated cleaning wipes for surface preparation in the field
• Heat Guns: For activating cure or disassembling high-strength bonded components
• Measuring Tools: Micrometres and bore gauges for assessing clearances accurately

Safety Information

Retaining compounds are chemical products that require proper handling and storage to ensure user safety and product effectiveness:

Personal Protection: Always wear appropriate PPE including nitrile gloves and safety glasses when handling uncured compounds. Work in well-ventilated areas or use local exhaust ventilation to minimise inhalation exposure to vapours.

COSHH Compliance: Consult the product Safety Data Sheet (SDS) before use and ensure your risk assessment covers the specific hazards of anaerobic adhesives. Store in accordance with manufacturer recommendations, typically in a cool, dry place away from heat sources.

Skin Contact: If retaining compound contacts skin, wash immediately with soap and water. Do not use solvents on skin. These adhesives can bond skin rapidly, so exercise particular care during application. If accidental bonding occurs, gently peel or roll bonded skin apart rather than pulling directly.

Disposal: Dispose of empty containers and waste materials in accordance with local authority requirements. Uncured material may require disposal as chemical waste rather than general workshop refuse.

Frequently Asked Questions

Can retaining compounds be used on worn or oversized bearings?

Yes, bearing fit retaining compounds are specifically formulated to fill larger gaps up to 0.38mm, making them ideal for salvaging worn assemblies that would otherwise require expensive machining or component replacement. This makes them particularly valuable in maintenance situations where tolerances have deteriorated through wear.

How do I remove a component secured with retaining compound?

Disassembly methods depend on the compound strength. Medium-strength retainers typically release when heated to approximately 250°C using a heat gun or torch. High-strength permanent formulations may require more aggressive heating or mechanical methods. Always consult the product technical data sheet for specific removal procedures.

What's the difference between retaining compound and thread locker?

Whilst both are anaerobic adhesives, retaining compounds are formulated for cylindrical assemblies and can fill larger gaps (up to 0.5mm), making them suitable for bearing fits and bush installations. Thread lockers are optimised for threaded fasteners with their characteristic helical gaps and different strength requirements.

Do I need to clean oily surfaces before applying retaining compound?

Standard retaining compounds require clean, degreased metal surfaces for optimal performance. However, oil-tolerant formulations like Bondloc B603 are designed to cure despite light oil contamination, making them ideal for maintenance situations where thorough degreasing isn't practical or possible.

How long does retaining compound take to cure?

Fixture time (handling strength) typically ranges from 5 to 30 minutes depending on the specific product and substrate materials. Full functional strength usually develops within 24 hours at room temperature. Cure speed can be accelerated using activators or heat, which is particularly useful in production environments or cold conditions.